Method of utilizing an implant in a human breast

ABSTRACT

A method for utilizing an implant in a breast cavity in a human breast, comprising forming a substantially radio-opaque implant constructed of biodegradable material, the biodegradable material being elastic, compressible, expandable, and allowing for in-growth of fibrous tissue into the biodegradable material, the substantially radio-opaque implant being compressed during implantation in the breast cavity; and the substantially radio-opaque implant configured to expand in the breast cavity when implanted within the breast cavity for supporting the tissue surrounding the breast cavity.

STATEMENT OF PRIORITY

This application is a continuation in part of U.S. patent applicationSer. No. 11/168,785 filed on Apr. 19, 2005 which is a continuation inpart of U.S. patent application Ser. No. 10/627,718 filed Jul. 28, 2003,now U.S. Pat. No. 6,881,226, which is a continuation of U.S. patentapplication Ser. No. 09/828,806 filed Apr. 10, 2001, now U.S. Pat. No.6,638,308, which is a division of U.S. patent application Ser. No.09/169,351, filed Oct. 9, 1998, now U.S. Pat. No. 6,214,045, whichclaims the benefit of U.S. Provisional Application Ser. No. 60/061,588,filed Oct. 10, 1997, U.S. Provisional Application Ser. No. 60/077,639filed Mar. 11, 1998, and U.S. Provisional Application Ser. No.60/091,306, filed Jun. 30, 1998, the disclosures of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

Radiation for breast cancer currently mainly consists of full breastradiation, which imparts radiotherapy to the full area of the breast. Itnecessarily involves surrounding structures such as, but not limited tothe heart, lungs, esophagus, chest wall, ribs and other structures thatare in close proximity to the breast. A new concept of partial breastradiation targeting the area of the breast involved by cancer iscurrently gaining popularity. Studies thus far indicate that it is aseffective as full breast radiation and eliminates damage to thesurrounding organs. Partial breast radiation is currently beingdelivered through temporarily implanted balloon catheters such as butnot limited to the MAMMOSITE or the CONTURA. This process involvesplacing a radioactive seed or target down the catheter for a briefperiod of time, over three to five days.

Unfortunately, this method of utilizing a catheter and radioactive seedhas a number of drawbacks. Utilizing a concentrated dose of radiationover a short period of time in the form of a radioactive seed plantedthrough means of the catheter or other surgical means creates amultitude of side effects such as fat necrosis, seromas, hematomas,infection and undesirable cosmetic outcomes. When a lumpectomy isperformed, a temporary balloon catheter is put into place with thecatheter extruding from the breast. This allows an opening into thecavity which increase the chance of infection. Furthermore, this methodrequires the physician to wait for the pathology report to indicatemargins of the specimen to be free of cancer (as well as the absence ofcancer from the lymph nodes) before the temporary balloon can be removedand a Mammosite, Contura or other external catheters can be implanted inpreparation for partial breast radiation therapy. This sequence ofprocedures is preferred as soon as possible following lumpectomy. Anadditional drawback to the catheter methodology is the need to aspirateair from the lumpectomy cavity. Air in a lumpectomy cavity creates “hotspots” or high heat conditions within the cavity when subjected toradiation therapy, thereby causing burns and other undesirable sideeffects. Accordingly, it is desirable to aspirate or remove the air,most commonly with a syringe and needle. Unfortunately, the currentmethod catheter may be punctured by the needle during aspiration,creating problems for its subsequent use and effectiveness in treatment.These problems are resolved by use of the proposed method. We proposethe use of external beam radiation delivered through a multi-directionalstereotactic radiation source such as but not limited to the CYBERKNIFE,the BRAIN LAB, and other external beam sources. However, external beamradiation requires a sufficiently identifiable target. Currently,external beam radiation is used on solid organs such as the liver thatcontains a tumor or the head of the pancreas that contains a tumorwhereby a gold seed is implanted in these structures and acts as a guidefor focusing the external stereotactic beam. The solid tissue of theseorgans provides a stable, non-shifting environment for placement of theseed which acts as a target for the external beam source. The use of thecatheter in breast tissue has been previously necessary due to thepresence of primarily fatty tissue in the breast, precluding a stableenvironment for placement of a small seed or target. In fatty tissue, asmall seed or target would move from the intended target site, renderingthe therapy ineffective. The breast is an external structure,constructed primarily of fatty tissue, unlike the other mentionedorgans. Consequently, what is necessary then, is a means of stabilizinga seed or other target source within the fatty tissue of the breast,which seed or other target source may then be utilized as a target in anew method of partial breast radiation. The proposed invention addressesthis problem. Being an external structure also, the breast is alsocapable of being more rigidly fixed for targeting in stereotacticradiation machines than the internal organs and is therefore a goodcandidate for utilizing partial irradiation through careful targeting ofthe internal implant and/or marker.

U.S. Pat. No. 6,214,045, issued to the applicant, discloses a breastimplant of resorbable material sized to replace excised tissue andallowing for in-growth of fibrous tissue to replace the implant. Theimplant may be elastic, compressible, and expandable and may furthercontain diagnostic substances. The specification of U.S. Pat. No.6,214,045 is incorporated by reference herein. Certain diagnosticsubstances are identified in the '045 patent as “x-ray opaque ormetallic material for identification of the area.” Many embodiments ofthe implants described in the '045 patent may act as appropriate targetsfor stereotactic radiation sources as radiopaque targets. Biodegradablematerials such as, but not limited to, collagen and other suitably densebiocompatible materials, may be configured suitably radiopaque. Theimplants may alternatively be constructed of two or more differentmaterials or contain large amounts of air, which will also aid inacquisition and targeting by a suitable stereotactic radiation source.The implant may be shaped spherical to keep the lumpectomy cavity openin a more uniform manner however this is not always necessary as thelumpectomy cavity created by a biopsy procedure can be allowed topartially collapse and conform to the size or shape of the implant.Consequently, the implant shape may guide the external beam source inorder to allow a more specific area of the cavity to be radiated on oneside or the other, or uniformly circumferentially in the event ofutilizing a spherical implant. Particularly when compared with thepreviously disclosed catheter methodology, the ability to utilizevariously shaped implants is superior to the catheter, which isspherically shaped, in the event it is necessary to construct anon-spherical lumpectomy cavity to obtain the desired margins uponremoval of the cancer. The implant itself may act as the radio-opaquetarget or may have added to, more or less, the central portion of theimplant, a tiny metallic marker such as but not limited to a gold seedor a titanium seed to further aid as a guide for the external beam. Toconform with desired diagnostic needs and procedures, more than onemarker may be utilized in a single implant or more than one implant,placed within the lumpectomy cavity. Different marker materials may becontained within a single implant or within more than one implant placedwithin the lumpectomy cavity. Any metallic material, suitablysterilized, or other relatively dense biocompatible material, may beutilized as a marker within the implant. Where the external beamradiation is utilized, it accomplishes local brachytherapy with itsbenefits and the beam can be configured over varying time periods so asto eliminate many of the complications associated with the currentmethod of partial breast radiation, the balloon MammoSite or Contura.Use of the implants described in the '045 patent, addresses a multitudeof the current problems known to the medical industry such as but notlimited to cosmetic deformities, seromas, hematomas, infection and thelike while simultaneously providing the stable target necessary forsuccessful targeted radiation therapy. The 045 implants are configuredto keep the cavity open and support the surrounding tissue. This isparticularly important in radiation therapy as new tissue growth will beinhibited by the presence of radiation therapy. Accordingly, this methodand use of the implant will enable the lumpectomy site to retain itsconfiguration throughout radiation therapy and thereafter provide timefor regeneration and in-growth of new tissue upon termination ofradiation therapy. Once the external beam radiation is accomplished, theimplant may biodegrade over a period of time allowing ingrowth of thepatient's own natural tissues and, therefore reduce the risk ofundesirable cosmetic changes to the overlying skin or the breast. It mayalso have added to the implant hemostatic agents to minimize bleeding,other metallic markers, oncologic agents, antibiotics and the like.

Another advantage in the use of the implant for targeted partial breastradiation therapy is that the biodegradable implant can be inserted intothe breast at the time of the lumpectomy but radiation therapy my bedelayed without presenting complications in the maintenance of thetargeting means, treatment or to the patient. With the use of thecatheter methodology, the externally extruding catheter and its priordiscussed issues necessitates immediate radiation therapy treatment tominimize, to the extent possible, potential complications such asinfection and discomfort to the patient. Immediate radiation therapy isnot always preferred because the surgical wound is fresh and has nothealed. The use of radiation further retards healing and promotes seromaformation, infection, and cosmetic defects because of poor healing. Theproposed methodology, utilizing the implant, allows the implant to beplaced in the lumpectomy cavity and the wound surgically sealed. Thepatient may maintain a normal lifestyle and radiation therapy may bescheduled as appropriate in the particular case. The patient mayundergoe chemotherapy and can delay radiation therapy up to about 120days without decreasing the therapeutic effects of the radiation. Theimplant may degrade somewhat over a period of time while the breast ishealing to allow the lumpectomy cavity to compress down upon the implantor scar down around the implant shrinking the cavity and stablizing thetarget for future radiation. Future radiation thearapy may may beinitiated many days or weeks after the lumpectomy. Radiation therapy maybe discontinued, if necessary, and re-instituted as necessary, withinthe life of the biodegradable implant or, in the case of a marker, atany time thereafter. This accomplishes the prevention of hematomas orseromas, resulting in a better cosmetic outcome while maintaining astable target for future therapy or diagnosis.

DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts one embodiment of an implant placed within a breastlumpectomy cavity to act as a target for radiation therapy emissions.

FIG. 2 depicts an alternative embodiment of an implant placed within abreast lumpectomy cavity and containing an internal marker to act as atarget for radiation therapy emissions.

FIG. 3 depicts one example of an implant placed within a breastlumpectomy cavity and subjected to radiation therapy emissions.

FIG. 4 depicts an alternative embodiment of an implant containing aninternal marker to act as a target for radiation therapy emissions.

FIGS. 5A and 5B depict implants of various shapes and configurationsplaced within breast lumpectomy cavities.

FIG. 6 depicts a partially re-absorbed implant within a shrinking breastlumpectomy cavity.

FIG. 7 depicts a partially re-absorbed implant containing a metallicmarker within a shrinking breast lumpectomy cavity.

DETAILED DESCRIPTION OF THE DRAWINGS

In FIG. 1, a substantially spherical implant (100) is composed ofbiodegradable material and is placed within a breast lumpectomy cavity(110) following a biopsy or other surgical procedure. The implant may beconstructed of materials such as biodegradable foams, sponges, gels,liquids, or other biocompatible substances. The material is formed insuch a way that it can support surrounding breast tissue, assisting inbreast cosmesis by keeping the breast lumpectomy cavity from collapsing.The implant further functions as a radio-opaque target for external beamstereotactic partial breast radiotherapy. The implant can be constructedwith varying pore sizes thus allowing for example, more air to beincorporated into the implant, rendering the implant more radio-opaquewhile preventing the collection of air pockets within the breast cavitywhich create unsuitable conditions for radiation therapy. The implantdoes not need to be the exact size of the lumpectomy cavity, however.Breast tissue will collapse around the implant, keeping the cavity openand relatively equal distance from the center of the implant. Theimplant is of a sufficient size and solid consistency to allow astereotactic radiation source to be directed to the implant as a targetfor delivery of radiation therapy to the surrounding margins of thelumpectomy cavity in a precise configuration as determined by theradiotherapist.

In FIG. 2, the implant (100) of FIG. 1 further contains a gold seed,metallic seed, titanium clip or other suitably dense implant material(120) to aid in successful targeting of the implant area for astereotactic radiation source. Since margins can vary from patient topatient, the use of an implant material can serve as a guide forprogramming the stereotactic radiation unit. The target material may becentrally located within the implant or located about the periphery ofthe implant. One or more implant materials may be concurrently used asnecessary to conform the intended radiation therapy to the patient'sbreast cancer treatment. As the target material may or may not bebiodegradable, the implant material may remain available for extendedradiation therapy as necessary. Biodegradable material may have variableabsorption rates.

In FIG. 3, an example of multi-directional (stereotactic) radiationtherapy (160) targets a breast implant (100) in the breast lumpectomycavity (110), partially irradiating the breast within targeted margins(170) around the lumpectomy cavity (110).

In FIG. 4, an example of multi-directional (stereotactic) radiationtherapy (160) targets a breast implant (100) containing an internalmarker (120), in the breast lumpectomy cavity (110), partiallyirradiating the breast within targeted margins (170) around thelumpectomy cavity (110).

In FIG. 5A and FIG. 5B, an implant (100) in the breast lumpectomy cavity(110) may be configured to conform to the lumpectomy cavity excised tocreate sufficient margins for excision of cancer or in accordance withgood medical practice for the surgical procedure. The ability to conformthe implant to the cavity allows appropriate margins to be maintainedfor following radiation treatment and supports the surrounding breasttissue without deformation.

In FIG. 6, the implant (100) has partially reabsorbed as a consequenceof the passage of time. Unlike the prior art catheter, the implant canact as a target to the biopsy site for weeks or months afterimplantation, to allow for healing, chemotherapy or other issuesnecessitating a delay in radiation treatment. The surrounding breasttissue comprising the lumpectomy cavity collapses or generates growth asthe implant resorbs, holding the implant in place and the geometry ofthe breast tissue in static relation.

In FIG. 7, the resorbing implant (100) also contains one or more markers(120) to aid in targeting. Again, the implant and marker allow thetreating physician to delay radiation treatment pending healing,chemotherapy or other favorable reasons for delay.

1. A method for utilizing an implant in a breast cavity in a humanbreast, comprising: forming a substantially radio-opaque implantconstructed of biodegradable material, the biodegradable material beingelastic, compressible, expandable, and allowing for in-growth of fibroustissue into the biodegradable material, the substantially radio-opaqueimplant being compressed during implantation in the breast cavity; andthe substantially radio-opaque implant configured to expand in thebreast cavity when implanted within the breast cavity for supporting thetissue surrounding the breast cavity. 2-30. (canceled)
 31. The method ofclaim 1, wherein said substantially radio-opaque implant has a shapeselected to guide delivery of radiation therapy to margins around thebreast cavity.
 32. The method of claim 1, the substantially radio-opaqueimplant conforming to the shape of the breast cavity, and serving as atarget for delivery of radiation therapy to margins around the breastcavity, wherein a radiation beam directed to the substantiallyradio-opaque implant delivers radiation therapy to margins around thebreast cavity without materially irradiating the whole of the breast.33. The method of claim 32, wherein the radiation therapy is delivery ofa therapeutically effective dosage of radiation to said breast tissuesurrounding the substantially radio-opaque implant via a stereotacticradiation machine.
 34. The method of claim 33, wherein the radiationtherapy is delivery of multiple therapeutically effective dosages ofradiation to said breast tissue surrounding the substantiallyradio-opaque implant in a single treatment.
 35. The method of claim 32,wherein the radiation therapy is delivery of therapeutically effectivedosages of radiation to said breast tissue surrounding the substantiallyradio-opaque implant multiple times in a single treatment.
 36. Themethod of claim 32, wherein the radiation therapy is delivery of atherapeutically effective dosage of radiation to said breast tissuesurrounding the substantially radio-opaque implant via multidirectionalradiation therapy.
 37. The method of claim 32, wherein the radiationtherapy is delivery of a therapeutically effective dosage of radiationto said breast tissue surrounding the substantially radio-opaque implantvia image guided radiation therapy.
 38. The method of claim 32, whereinthe radiation therapy is delivery of a therapeutically effective dosageof radiation to said breast tissue surrounding the substantiallyradio-opaque implant via 3-D conformal radiation therapy.
 39. The methodof claim 32, wherein the radiation therapy is delivery of atherapeutically effective dosage of radiation to said breast tissuesurrounding the substantially radio-opaque implant via intensitymodulated radiation therapy.
 40. The method of claim 32 comprisinginitiating targeting of the radiation beam for delivery of the radiationtherapy 1 to 120 days subsequent to the placement of the substantiallyradio-opaque implant in the breast cavity.
 41. The method of claim 1,further comprising aspirating air from the breast cavity afterimplanting the substantially radio-opaque implant in the breast cavity.42. The method of claim 1, wherein the substantially radio-opaqueimplant is constructed of a porous material.
 43. A method for using animplant following a biopsy procedure in which a biopsy cavity was formedin a human breast, comprising: providing a substantially radio-opaqueimplant constructed of biodegradable material configured to allow forin-growth of fibrous tissue into and replacing the of biodegradablematerial, the biodegradable material being elastic, compressible, andexpandable; and configuring the substantially radio-opaque implant toconform to the shape of the breast cavity when implanted within thebreast cavity to support the tissue surrounding the breast cavity. 44.The method of claim 43, wherein said substantially radio-opaque implanthas a shape selected to guide the delivery of radiation therapy to themargins around the breast cavity.
 45. The method of claim 44,comprising: using the substantially radio-opaque implant within thebreast cavity as a target for delivery of radiation therapy to marginsaround the breast cavity during partial breast radiation therapy; anddirecting a therapeutically effective dosage of radiation to thesubstantially radio-opaque implant target such that the whole of thebreast is not materially irradiated.
 46. The method of claim 45 furthercomprising initiating a targeting of the delivery of the radiationtherapy 1 to 120 days subsequent to the placement of the substantiallyradio-opaque implant in the breast cavity.